Robot End-Effector Guidance Along Discrete Poses Without Jerky Motion
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Solution Overview
Problem
Existing robot control methods result in jerky movements and alternating attractions when manually guiding a robot-fixed reference due to resistance at grid points, leading to suboptimal movement control.
Innovation Solution
A method that applies driving forces based on the difference between the current pose and the closest permissible pose, using restoring forces to guide the robot along a sequence of discrete poses, with components dependent on speed to reduce jerky movements and improve stability, employing operational space control to manage these forces effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If robot control uses discrete grid points with alternating resistance and attraction forces, then the robot can be guided along a structured path, but the movement becomes jerky and unstable
Solution Approach 1:
The patent implements feedback by continuously calculating the difference between current pose and nearest permissible pose, then applying restoring forces proportional to this difference. This feedback mechanism guides the robot smoothly toward discrete poses without jerky movements, resolving the contradiction between structured path following and movement smoothness
Solution Approach 2:
The patent changes the control parameter from binary grid-point attraction to continuous restoring forces based on pose differences. By using speed-dependent damping forces and adjustable force constants, the system achieves smooth transitions while maintaining guidance along discrete permissible poses, eliminating jerky movements
2Manufacturing precision
If restoring forces are applied to guide the robot to nearest permissible poses, then path accuracy improves, but alternating attraction causes jerky movements
Solution Approach 1:
The patent introduces dynamic damping forces proportional to robot speed, which counteract the alternating attraction effects. The total force combines position-dependent restoring forces with velocity-dependent damping, creating smooth, controlled movement while maintaining accurate guidance to permissible poses, thus eliminating jerky movements
Solution Approach 2:
The system preliminarily calculates the nearest permissible pose and the required restoring force before actual movement occurs. By preparing the force field in advance based on current position, the robot experiences continuous, smooth guidance forces rather than sudden attractions, preventing jerky movements while maintaining pose accuracy
Data Source
Figure 1~2
AI summary
The invention relates to a method for moving a reference fixed on a robot, in particular an end effector (12), of a robot, in particular a multi-axis robot arm (10), on the basis of a number, in particular a sequence, of predefined, discrete, permissible poses (Xd,i-2, Xd,i-1, Xd,i, Xd,i+1, Xd,i+2) of the reference, comprising the step (S80), which is, in particular, repeated multiple times: - exerting drive forces on the robot via drives (11) thereof in order to move the reference to follow a manual guiding force exerted on the robot on the basis of a difference between a current pose {x{t)) of the reference and a first pose (Xnear) of the permissible poses closest thereto, such that, in the case of a deviation between the current pose and the first pose, the drive forces effect a return force on the reference according to the difference, wherein the return force corresponds to a restoring force from the current pose to the first pose, according to the difference, the component of which restoring force is suppressed in the direction of a bridging between the first pose and a second pose, adjacent thereto, of the permissible poses, such that the component of a total force effected by the drive forces on the reference in the direction of the bridging is independent of the difference; and/or at least one portion of the drive forces is dependent, in particular linearly, on velocities of the drives and/or a velocity of the reference.